WASHINGTON — A survey shows U.S. manufacturing activity expanded more slowly in March than February, held back by weaker growth in production and new orders. But factories hired at the fastest pace in nine months, an encouraging sign ahead of Friday's report on March employment.

The Institute for Supply Management said Monday that its index of factory activity slipped to 51.3 percent. The index fell from 54.2 percent in February, which was the fastest growth since June 2011.